Conventionally, ferroelectric ceramic compositions each composed of lead zirconate titanate (Pb(TixZr1-x)O3) or lead titanate (PbTiO3) as a main component have been widely used as piezoelectric elements. Non-Patent Document 1 and the like disclose (Ba,Sr)2NaNb5O15. Furthermore, Non-Patent Document 2 discloses Ba2AgNb5O15.
Non-Patent Document 1: J. Am. Ceram. Soc., 52(1976)276
Non-Patent Document 2: J. J. Appl. Phys., 13(1974)1291